Manufactures of textiles are continuously searching for compositions to enhance textile fiber performance and durability. In the carpet and floor coverings industry, for example, manufacturers desire compositions operable to render carpet fibers stain resistant as well as flame resistant. Fluorinated carbon compounds have been used extensively to impart water and oil repellency to textile and carpet fibers. Fluorocarbon compounds can provide both oil and water repellency simultaneously, unlike waxes, silicones, etc., which typically provide water repellency, but are somewhat oleophilic, and thus do not provide good oil repellency.
Fluorinated or perfluorinated alkyl compounds, when applied to fibers in sufficient amount, lower the surface tension of the fiber or fabric below the surface energy of water or oils that might be spilled onto the fabric. This allows these liquids to be removed before they can penetrate into the fiber or fabric. This is of great benefit for fibers and fabrics used in residential, commercial, and industrial settings as the useful life of the fibers and fabric is substantially increased.
Similarly, numerous flame retarding compounds have been developed for textiles, including carpets, to reduce or preclude the flammability of the natural or synthetic fibers contained therein. Inorganic and organic tin compounds have been used to reduce the flammability of polyamides. Moreover, aluminum compounds have also found applicability as flammability retardants. These compounds, however, have not demonstrated completely satisfactory results under several testing conditions.
In addition to developing stain repellant and fire retardant chemical species, manufactures have additionally developed techniques for effectively applying these chemical species to textile fibers. Manufactures, for example, have developed complex solutions and techniques to exhaust fluoropolymer compositions onto textile fibers. In view of these complex exhaustion solutions and techniques, several fiber compositions, including thermoplastic polyesters, remain resistant to accepting stain repellant and/or flame retarding chemical species.
Polytrimethylene terephthalate (PTT) is a polyester which demonstrates superior mechanical characteristics, weatherability, heat aging resistance and hydrolysis resistance making it an ideal candidate for carpeting, textiles and apparel, engineering plastics, nonwovens, films, and mono-filament applications. PTT is produced by condensation polymerization of 1,3-propane diol (PDO) and terephthalic acid.
PTT has been commercially available for over 50 years. Despite its advantageous physical and chemical properties, PTT has not found wide application due to the prohibitive cost of producing or obtaining PDO. However, in the 1990's, Shell Chemicals developed a low cost method of producing PDO suitable for PTT production. Moreover, an environmentally friendly process has subsequently been developed wherein a genetically modified strain of E. coli bacteria is fed a refined corn syrup and undergoes a fermentation process resulting in the production of PDO.
With cost efficient and environmentally friendly methods currently available for producing PDO, PTT is a viable replacement for polyolefin, polyamide, and other polyester fibers in textile and carpet applications. Nevertheless, PTT has demonstrated less than desirable flammability properties in textile and carpet applications, especially in applications wherein a fluoropolymer has been applied to textile fibers and carpet fibers.